As an example of a storage system, there is a storage system in which a daisy chain connection is established, via expanders, between a plurality of storage units (storage devices) such as hard disk drives (HDD) and a control device for controlling the plurality of storage units (for example, Patent Literature 1). With such a storage system, a communication protocol such as a SAS (Serial Attached SCSI) is used in order to perform peer-to-peer communication between the control device and the storage units.
A storage system which uses the SAS as the above-mentioned communication protocol is configured so that a plurality of SAS expanders are connected serially to a SAS controller in a control device and the plurality of storage devices are connected to each SAS expander. According to a standard specification of the SAS (Non-patent Literature 1), if a link failure such as communication incapability occurs in a SAS expander, another SAS expander immediately followed by the above-mentioned SAS expander notifies the SAS controller of a change in the configuration of the immediately following SAS expander. However, the storage system is designed so that the SAS controller cannot identify, with that notice, which SAS expander has sent the above-mentioned notice. So, the SAS controller which has received the notice from the SAS expander sends a confirmation command to the SAS expander in order to identify at which location the failure occurred. Then, the SAS controller identifies at which location the link failure occurred, based on a response result from the SAS expander.